This is a clinical project, with the primary purpose of managing and treating the NIH kidney recipients and collecting long-term clinical data. The overall evaluation of the NIH kidney transplant program will be performed toward 2011, when most participants will have completed the protocols. The following is an example of analysis of the transplant database, presented at the Annual American Society of Nephrology meeting in 11/08. CINACALCET IMPROVES BONE DENSITY IN POST KIDNEY TRANSPLANT HYPERPARATHYROIDISM ME Cho1, Z Duan2, CE Chamberlain3, JC Reynolds4, MS Ring1, RB Mannon5 1 Kidney Disease Branch, NIDDK;2Office of the Director, NIDDK;3Clinical Center Pharmacy, 4Nuclear Medicine, Clinical Center, NIH, Bethesda, MD, 5Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL ABSTRACT In patients with persistent hyperparathyroidism following kidney transplantation, the recent availability of cinacalcet has provided a possible alternative to parathyroidectomy. However, the impact of this treatment on bone mass density (BMD) is not known. In all 163 kidney and kidney/pancreas transplants performed in our center from 1999-2007, we compared recipients who received cinacalcet for persistent hypercalcemia and hyperparathyroidism following renal tx (n=8;CIN) with up to 2 other post tx patients matched for age, sex, and race (n=15;CON). The outcome of the study was BMD changes from baseline to 12, 24, and 36 months post renal tx. Repeated Measures Mixed model was used to assess the difference of BMD change between two groups. Cinacalcet therapy was started at a median of 9 months (range;1, 24 months) post tx with a mean dose 5629 mg/d (mean duration;1.6 years, range;1, 2.1). The mean baseline age, serum creatinine and BMI were not different in both groups. Cinacalcet therapy was associated with significant reduction of serum calcium compared to control. While there was no significant difference in BMD change between CIN and CON in the spine or forearm, cinacalcet therapy was associated with greater BMD increase at the hip over the 36-month post transplant period. Cinacalcet was well tolerated. No one developed clinically significant hypocalcemia. Our results suggest that cinacalcet has a small but favorable effect on bone density following kidney transplantation. However, a larger prospective trial is needed to better define the impact of cinacalcet on bone health.